Get quality and the supplier looking at the same samples under the same inspection conditions first. Otherwise you'll buy the pad that wins an argument under somebody's favourite lamp. Do you know what the finish looked like before gripping?
Then you need fresh identified samples with their starting condition checked. I'm not saying the pads are innocent, just that the current box can't tell you which marks they made.
Who gets the replacement-pad instructions after this? If it takes the supplier's favourite technician to fit each set, your shift will inherit another callout instead of a usable tool.
Good point. And the comparison has to cover holding and release, not just appearance. A spotless part that won't let go isn't the bargain anyone asked for.
Have you compared the samples under the agreed inspection method yet? I'd be interested whether the visible rings changed the ranking of the proposed pads, before the holding and release results were added.